Answer:
There are none. God created the world.
That our Universe has, for the last 13.7 billion years, been expanding at pretty much a constant rate, is pretty much irrefutably shown by Hubble's Constant and the nature of cosmic microwave background radiation. Also by the ratio of hydrogen to helium in our Universe.
All other hypotheses can do nothing more than say, "I don't know WHY these three observations are the way they are -- they just ARE."
The Big Bang Theory (NOT a hypothesis, any more than gravity is just a hypothesis) does NOT attempt to explain what occurred prior to the start of this expansion. If just states what has happened since.